1. Field of Invention
The invention relates to an extruder device.
2. Description of the Prior Art
Conventional extruder devices exhibit an extruder worm; and said devices are driven by a worm drive by means of a gear transmission unit. However, such gear transmission units are mechanically complicated and maintenance intensive, so that recently attempts have been made to drive the extruder worms directly—that is, without a gear transmission unit.
With the emergence of the so-called hollow shaft motors, it is now possible to build such directly driven extruder devices with smaller dimensions. Thus, for example, EP 1 182 027 A1 proposes an extrusion device, wherein the extruder worm exhibits a connecting section, which is inserted into a bushing and then is or will be connected to the same so as to be rotationally rigid. Therefore, the connecting section and the bushing are surrounded by the aforesaid hollow shaft motor, which can transfer the drive torque, generated by said motor, to the bushing by means of the torque-transmitting elements. Due to the fact that the hollow shaft motor surrounds the connecting section of the extruder worm, the overall length of the entire extrusion device is relatively short.
However, the drawback with this construction is that the torque-transmitting elements are difficult to access. Hence, the advantage of the somewhat shorter overall length is more than frustrated by longer continual maintenance work.
Therefore, the object of the present invention is to improve a prior art gearless extrusion device in such a manner that the torque-transmitting elements are easier to access.